First Layer Quality

[Croy5199]

I am printing a gear on a raft. The gear is parallel to the bed with teeth in Z axis
The first layer is always;
1) printer with first layer bigger than the rest of the layers.
2) print quality of bottom (first layer) not as good as expected. i.e. smooth finish as if moulded.

Please can someone give me some advice on how to improve on above.

PS I have checked Hot-End to bed and it is a snug 0.2mm
This is a Pro2

[Markus64]

Can you show pictures please?
What kind of filament are you printing?
I only use 0.2 mm nozzle spacing for PET-G. For PLA and ABS, 0.08 - 0.1 mm nozzle spacing works best for me.

[Croy5199]

Please see included photos:
Gear1 on edge shows the first layer (on the right side) where the first layer protrudes all round. This was printed on a raft so this is not hotend to bed calibration.
Gear2 is the top finish, I think this is acceptable.
Gear3 is the first layer on the raft and looks crap.

[Markus64]

Unfortunately you did not answer my question about which material you print with.

I ALWAYS print such parts without a raft!
Assuming your layer height is 0.2 mm, then set your first layer settings like this:
First layer height 0.2 mm
Leave the flowrates at 100%.
Reduce printing speed significantly.
Image 3 shows me that you should fine-tune the retraction settings including coasting and wipe.

[Croy5199]

Hi Markus64

Apologies, this was BASF PAHT Carbon Fibre 1.75mm and printed with a 0.4mm hard nozzle.
First layer at 0.2mm
Flowrates are 100%
Tomorrow I'll try reducing print speed then the others.

[Steven@Raise3D]

Hi Markus64

Apologies, this was BASF PAHT Carbon Fibre 1.75mm and printed with a 0.4mm hard nozzle.
First layer at 0.2mm
Flowrates are 100%
Tomorrow I'll try reducing print speed then the others.

What size nozzle are you printing with?

[Croy5199]

0.4mm hard steel

[Steven@Raise3D]

[quote="Croy5199"]0.4mm hard steel[/quote

For this type of material, we as well as the filament manufacture recommend that it be printed with a 0.6mm hardened nozzle or larger. The filament profile that is on our Open filament program is using a 0.6mm nozzle. This is most likely where a lot of your printing issues are coming from as the CF particles are too large to pass through a 0.4mm nozzle.

[Croy5199]

Thanks Steve for responding.

Just realised that the Raise3D so-called "Hard Nozzle" is not Steel but brass with coating. Why would Raise3D make an inferior produce that implies it suitable for Carbon Fibre when it is marginally better than the std brass.

[ccclarke]

It probably comes down to a tradeoff between price and thermal efficiency. The nickel-plated brass (hardened) nozzle conducts heat better than an all-steel nozzle (nearly 4X).

Common metals ranked by thermal conductivity

Rank Metal Thermal Conductivity [BTU/(hr·ft⋅°F)]

1 Copper 223
2 Aluminum 118
3 Brass 64
4 Steel 17
5 Bronze 15

[Steven@Raise3D]

Thanks Steve for responding.

Just realised that the Raise3D so-called "Hard Nozzle" is not Steel but brass with coating. Why would Raise3D make an inferior produce that implies it suitable for Carbon Fibre when it is marginally better than the std brass.

I believe we are working on a fully hardened nozzle, as to when that will be released I could not say. There is a lot of testing that goes on with these things to ensure that everything will be seamless if a customer wanted to use it. For now, I would still recommend that you use our standard 0.6 V3 hardened nozzle.

[Croy5199]

It probably comes down to a tradeoff between price and thermal efficiency. The nickel-plated brass (hardened) nozzle conducts heat better than an all-steel nozzle (nearly 4X).

Common metals ranked by thermal conductivity

Rank Metal Thermal Conductivity [BTU/(hr·ft⋅°F)]

1 Copper 223
2 Aluminum 118
3 Brass 64
4 Steel 17
5 Bronze 15

Steel Tungsten 1% is around 61, Tungsten is >100 and Vanadium in in the 30s.
When you weigh up material cost vs longevity and time down due to maintenance, I'm sure a hard metal will overrule the desire to keep it cheap.